

A004014


Norms of vectors in the b.c.c. lattice.
(Formerly M2347)


1



0, 3, 4, 8, 11, 12, 16, 19, 20, 24, 27, 32, 35, 36, 40, 43, 44, 48, 51, 52, 56, 59, 64, 67, 68, 72, 75, 76, 80, 83, 84, 88, 91, 96, 99, 100, 104, 107, 108, 115, 116, 120, 123, 128, 131, 132, 136, 139, 140, 144, 147, 148, 152, 155, 160, 163, 164, 168
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

0,2


COMMENTS

Integers such that A004013(n) is nonzero.  Michael Somos, Jul 28 2014


REFERENCES

J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", SpringerVerlag, p. 116. (Chapter 4 section 6.7)
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


LINKS

Robert Israel, Table of n, a(n) for n = 0..10000
G. Nebe and N. J. A. Sloane, Home page for this lattice
Index entries for sequences related to b.c.c. lattice


MAPLE

f:= JacobiTheta2(0, z^4)^3+JacobiTheta3(0, z^4)^3:
S:= series(f, z, 1001):
select(t > coeff(S, z, t) <> 0, [$0..1000]); # Robert Israel, Oct 18 2015


MATHEMATICA

f = EllipticTheta[2, 0, z^4]^3 + EllipticTheta[3, 0, z^4]^3; S = f + O[z]^200; Flatten[Position[CoefficientList[S, z], _?Positive]  1] (* JeanFrançois Alcover, Oct 23 2016, after Robert Israel *)


CROSSREFS

Cf. A004013.
Sequence in context: A222269 A310011 A047458 * A243177 A113294 A169691
Adjacent sequences: A004011 A004012 A004013 * A004015 A004016 A004017


KEYWORD

nonn,nice,easy


AUTHOR

N. J. A. Sloane.


EXTENSIONS

More terms from Sean A. Irvine, Oct 17 2015


STATUS

approved



